Appeal a Health Insurance Claim Denial

Your health insurance claim was denied. Before you do anything else, pull out the denial letter and find two things: the reason code and the appeal deadline. Everything in your appeal will target that reason code specifically — a generic "please reconsider" letter will not work. Here is how to approach the most common denial reasons, starting with the ones that are overturned most often: - Coding or billing errors account for a surprising share of denials and are the easiest to fix. Your provider submitted a wrong ICD or CPT code, or the diagnosis and procedure codes didn't match. Contact your provider's billing department, get the corrected codes, and request reprocessing. This often resolves without a formal appeal at all. - Medical necessity denied is the denial that scares patients most — but it has a strong overturn rate when you bring the right evidence. The insurer's medical reviewer (who often lacks specialty expertise in your condition) decided the treatment wasn't necessary. Your appeal needs a detailed letter from your treating physician explaining why this specific treatment is required for your specific diagnosis, what alternatives were tried and failed, and citations to clinical guidelines (NICE, AMA, specialty society recommendations) supporting the treatment. Request a peer-to-peer review where your doctor speaks directly with the insurer's reviewer — many denials flip at this stage. - Missing prior authorization is frustrating because it may not have been your fault. If authorization was obtained, attach the approval document. If your provider failed to request it, your appeal should argue that you — the patient — should not be penalized for an administrative error you had no control over. If the insurer failed to respond to the authorization request within their required timeframe, that constitutes automatic approval in many states. - Out-of-network provider treatment is often covered when no in-network specialist was available within a reasonable distance or wait time, or when you received emergency care. Document your search for in-network providers and why out-of-network was the only realistic option. - Pre-existing condition exclusion: In the US, the ACA prohibits pre-existing condition exclusions for marketplace plans. If your plan is ACA-compliant, cite the law directly. For non-ACA plans (short-term, grandfathered), check the specific policy language — the exclusion may still be narrower than the insurer claims. - Treatment deemed experimental: Include evidence that the treatment is FDA/EMA-approved, recommended in current clinical guidelines, and has peer-reviewed evidence of efficacy. Expert letters from specialists in the field carry significant weight here. - Coverage limits, untimely provider filing, duplicate claim flags, and coordination of benefits disputes are less common but equally appealable — each requires documentation showing the insurer's basis is factually incorrect.